Cannot access public folders from Outlook 2003/2007 after moving users mailboxes to Exchange 2010.

So you have installed Exchange 2010 into your existing environment, replicated your public folders over and through your diligence you have verified that all hierarchy and content is showing up on your Exchange 2010 public folder store. Next you start migrating users over and everyone is just plugging away until one of your users try to access the public folders.

Your users have Outlook 2003 and/or Outlook 2007, as both clients can and will face this issue depending on your encryption requirements and settings. They report that they can log into their mailbox just fine however, when they click on public folders they get a error message like the following:

Or:

One of the settings that can cause this behavior is the RpcClientAccess EncryptionRequired on the server is set to $true for the public folder store which is the default setting. And it is set to  $false on the mailbox database (default = $true) and then lastly encryption required is off for the client.

*Note*

The default settings for Outlook 2003 encryption required is “off” and then in Outlook 2007 encryption required is “on”.

The common mistake we are starting to see here is that you know your clients have encryption required turned off in their outlook settings. So while setting up the servers or troubleshooting outlook logon testing you turn off the encryption required setting for the mailboxes but forget or miss the setting for the public folders like so. :

These settings for the client are configured through the “Tools” > “Email Accounts” or “Account Settings” > “Change Account” > “More Settings” option like below.

Outlook 2003

Outlook 2007

Just to reiterate by default EncryptionRequired is turned on ($True) and can be check with the Get-RpcClientAccess command like below:

If you want to see all your settings then format list that command for a detailed view.

Get-RpcClientAccess | fl

You can change these encryption settings using the Set-RpcClientAccess commands:

Set-RpcClientAccess –Server:<servername> –EncryptionRequired:$False

Or

Set-RpcClientAccess –Server:<servername> –EncryptionRequired:$True

The bottom line:

You have to have these settings all the same for the Mailbox, Public Folders and the Client for all features to work if your clients use Outlook. I highly recommend having encryption turned on in your environment to protect the data passing across your wires.